The new moon is believed to be no more than twelve miles in diameter and may not consist of more than a collage of rocks. The moon, called S/2004 N 1, was discovered by Mark Showalter with the aid of the Hubble telescope.
The find is noteworthy given that the small size of the moon makes it difficult to spot. The light being radiated off its surface (the primary means of identification) is 1/100,000,000th of that which the human eye can observe in the smallest of stars.
Showalter regularly observes the arcs of Neptune. He said that the orbits that arcs and moons make around planets are relatively fast and that tracking them via telescope is similar to how photographers shoot athletes in motion.
Showalter admits that finding the new moon was a stroke of luck. He had merely rotated the telescope a few ticks just for kicks and giggles when he spotted the new moon approximately 65,400 miles between the orbits of moons Proteus and Larissa.
“We had to devise a way to follow their motion in order to bring out the details of the system,” Showalter said in a statement.
“It’s the same reason a sports photographer tracks a running athlete — the athlete stays in focus, but the background blurs.” After realizing what he had found, Showalter located the same white dot in Hubble images taken between 2004 and 2009, allowing him to figure out the moon’s orbit.
The new moon completes a full orbit around Neptune in 23 hours.
Tiny, 12-mile-wide moon found circling Neptune by Hubble telescope